1. Field of the Invention
The present invention relates to a mobile station, such as a mobile phone terminal, a personal digital assistant (PDA), a note-type personal computer or the like, which is provided with a sound speaker.
2. Description of the Related Art
A mobile station, such as a mobile phone terminal, a personal digital assistant (PDA), a note-type personal computer or the like, contains a sound speaker in a casing of the mobile station to emit sounds for a moving picture, a game or the like. Also, when the sound speaker is used as a music sound speaker, it must have a relatively large size before a high quality sound can be obtained. In a case where the mobile station is a mobile phone terminal, the sound speaker is further used as a ringer when an incoming call is received. Namely, although a casing of the mobile phone terminal is relatively small, it must be provided with the sound speaker plus a talking speaker for a telephone call.
On the other hand, recently, there is a trend in mobile stations toward miniaturization. Thus, it is necessary to effectively arrange various electronic parts or elements before the miniaturization of the mobile station can be achieved. For this reason, conventionally, the sound speaker is frequently contained in the casing of the mobile station such that a sound emitting face of the sound speaker is in contact with an inner wall face of a bottom wall portion of the casing. In this case, it is difficult or impossible to deliver a sufficient volume of sound from the sound speaker to a user or listener. Especially, a high frequency sound cannot be delivered from the sound speaker to the user or listener because the high frequency sound exhibits a strong directivity.
Therefore, it is proposed that a sound hole is formed in a side wall portion or a front wall portion of the casing, and that the sound hole is connected to the sound emitting face of the sound speaker through a sound duct, as disclosed in, for example, JP-A-2001-119773, JP-A-2001-197182 and JP-A-2001-189981. With these arrangements, it is possible to deliver a sufficient volume of sound from the sound speaker to a user or listener. Nevertheless, the connection of the sound hole and the sound emitting face of the sound speaker through the sound duct is very troublesome, resulting in an increase in assembly cost of the mobile station.
On the other hand, there are various sound speakers which are used in mobile stations, as disclosed in, for example, JP-A-2000-244993, JP-A-2003-111194 and JP-A-2003-244787. In each of these sound speakers, in order to deliver a sufficient volume of sound to a user or listener, it is necessary to form a sound hole in a side wall portion or a front wall portion of the casing, and the sound hole must be connected to the sound emitting face of the sound speaker by using a sound duct. Thus, similar to the above-mentioned cases, the connection of the sound hole and the sound emitting face of the sound speaker through the sound duct is very troublesome, resulting in an increase in assembly cost of the mobile station.